Speed violation. - NASA ASRS

Attributes
ACN	300368
Time
Date	199503
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : gsh airport : mdw
State Reference	IN
Altitude	msl bound lower : 10000 msl bound upper : 10000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : flight engineer pilot : atp pilot : cfi
Experience	flight time last 90 days : 240 flight time total : 22000 flight time type : 9000
ASRS Report	300368
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 75 flight time total : 8000 flight time type : 75
ASRS Report	300474
Events
Anomaly	non adherence : clearance other anomaly
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

During descent inbound to cross the drivr fix at 10000 ft, ATC advised me to maintain 320 KTS. This was an increase of 20 KTS above my normal descent speed of 300 KTS. I complied, but when I leveled off at the drivr intersection, at 10000 ft, I began to slow to 250 KTS. This apparently caused a backup of traffic behind me and chicago ATC wanted to know why I had slowed. I advised that I had slowed in preparation for the next crossing restr and that my understanding of the clearance was to maintain 320 KTS in the descent - not until advised by ATC. Apparently ATC is of the other opinion. I offered and did increase my speed again, but still got chewed out by the current controller and was then told to switch back to the prior controller who also chewed me out. I don't feel that I was advised to maintain 320 KTS until advised and my first officer agrees with me. While we were descending to 10000 ft, we actually discussed the speed to program at the drivr intersection. I did call and discuss the situation with an ATC supervisor at ZAU and explained my position. He was receptive. I feel the speed instructions were not clear.

Original NASA ASRS Text

Title: SPD VIOLATION.

Narrative: DURING DSCNT INBOUND TO CROSS THE DRIVR FIX AT 10000 FT, ATC ADVISED ME TO MAINTAIN 320 KTS. THIS WAS AN INCREASE OF 20 KTS ABOVE MY NORMAL DSCNT SPD OF 300 KTS. I COMPLIED, BUT WHEN I LEVELED OFF AT THE DRIVR INTXN, AT 10000 FT, I BEGAN TO SLOW TO 250 KTS. THIS APPARENTLY CAUSED A BACKUP OF TFC BEHIND ME AND CHICAGO ATC WANTED TO KNOW WHY I HAD SLOWED. I ADVISED THAT I HAD SLOWED IN PREPARATION FOR THE NEXT XING RESTR AND THAT MY UNDERSTANDING OF THE CLRNC WAS TO MAINTAIN 320 KTS IN THE DSCNT - NOT UNTIL ADVISED BY ATC. APPARENTLY ATC IS OF THE OTHER OPINION. I OFFERED AND DID INCREASE MY SPD AGAIN, BUT STILL GOT CHEWED OUT BY THE CURRENT CTLR AND WAS THEN TOLD TO SWITCH BACK TO THE PRIOR CTLR WHO ALSO CHEWED ME OUT. I DON'T FEEL THAT I WAS ADVISED TO MAINTAIN 320 KTS UNTIL ADVISED AND MY FO AGREES WITH ME. WHILE WE WERE DSNDING TO 10000 FT, WE ACTUALLY DISCUSSED THE SPD TO PROGRAM AT THE DRIVR INTXN. I DID CALL AND DISCUSS THE SIT WITH AN ATC SUPVR AT ZAU AND EXPLAINED MY POS. HE WAS RECEPTIVE. I FEEL THE SPD INSTRUCTIONS WERE NOT CLR.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.